1. Field of the Invention
The present invention relates to a technology for simplifying a mechanism for detecting a status in an image forming device and reducing a number of components of the image forming device.
2. Description of the Related Art
Since an image forming device such as a printer fuses toner on paper to print out an image, the image forming device cannot print out an image when the toner runs out. Therefore, the image forming device is required to monitor a remaining amount of the toner at all times. A conventional image forming device includes an optical sensor for detecting the remaining amount of the toner.
When the conventional image forming device determines that the toner has run out according to a detection result of the optical sensor, a fact that the toner has run out is displayed on a display or the like. When an operator confirms the display, the operator opens a front cover and takes out and replaces a developing unit along with a toner cartridge (a container accommodating the toner).
The optical sensor, which monitors the remaining amount of the toner, is provided on a path along which the developing unit passes when taken out by the operator. Therefore, when the operator replaces the toner cartridge, the optical sensor is required to be retracted beforehand. In the conventional image forming device, a driving mechanism such as a motor is provided for moving the optical sensor to a retracted position. At a point in time when an open-close sensor detects that the front cover has been opened, the driving mechanism is driven to move the optical sensor to the retracted position. That is, the conventional image forming device requires the driving mechanism for moving the optical sensor and a control processor for controlling the driving mechanism.